VARIABLE STRUCTURE OBSERVER DESIGN FOR FLEXIBLE-LINK MANIPULATOR CONTROL

Observers are required to estimate the states, which are not directly measured. In this paper, a robust observer is developed for estimating the states of flexible link manipulators. The developed observer uses the sliding mode approach to improve the tracking and convergence performance of a quasi-linear observer. The observer stability and limitations are proved using a hybrid approach of Lyapunov-based and variable structure system techniques. The design procedure of the observer is presented and applied to a two-link, three-degrees of freedom manipulator with flexible links. The observer is used in real-time applications due to its simple structure. Simulation results show excellent performance for the observer even with the change of payload. Experimental results for implementing the observer on a 3D manipulator with flexible links are demonstrated.